implantation of silicon or germanium into silicon surface region prior
to source/drain doping implants; the goal is to pre-amorphize Si and by doing so to suppress channeling during subsequent source/drain implants; better control of the depth of implanted junctions is achieved.

channeling

effect occurring during implantation into crystalline solids; implanted specie may enter open "channel" in crystal lattice as a result of which it may penetrate the solid deeper than other implanted species subjected to collisions with atoms in the lattice; probability of channeling increases with implant energy.

shallow junction

term typically refers to a depth of the source and drain regions in advanced CMOS; scaling rules require continued reduction of the junction depth; can be as shallow as 10 nm.